Field of the Invention
The present invention relates to an electric storage device, equipment, and a control method.
Discussion of the Background
U.S. Patent Application Publication No. 2015-0137752 Specification describes charging and discharging performed by an electric vehicle in the vehicle to grid (V2G). The V2G is a system for interchanging electric power between a power system including a commercial power grid and an electric vehicle. When the electric vehicle is not in use as transportation means, an electric condenser installed in this electric vehicle is used as one of power storage facilities in the commercial power grid. Thus, the electric vehicle joining the V2G and the power system interchange electric power bidirectionally. The electric vehicle joining the V2G performs any one of: continuous discharging for maintaining supply-demand balance in the power system; and charging and discharging for stabilizing frequencies in the power system. Electric power acquired by the continuous discharging of the electric vehicle for maintaining supply-demand balance is used as “spinning reserve” of the power system. Meanwhile, electric power interchanged by the charging and discharging of the electric vehicle for stabilizing frequencies is used for “frequency regulation” of the power system. In both cases, the electric vehicle helps to stabilize the power system.